'7.7-" 


Property  of  the  United  Si 


Second  edil  ion 


U.S.  DEPARTMENT   OF  AGRICULTURE, 

Bl  l:i  A.1     OF   PLANT   INDUSTRY     I  ircular  No.  1. 
B.   I    GA]  l  ■  >fl  AY.  Chief  of  Bureau. 


SELF-BOILED  LIME-SULPHUR  MIXfURE 
AS  A  PROMISING  FUNGICIDE. 


-    I  L 

\V.    M.    M'OTl. 


'      <-*  *■•  **^ 


S.  DEPOSITORY 


1'aiiioi  ( 1018T  en  Charge  of  <  >rch  ird  Spraying  Dem<  instb  ^tions 

1  N \  I  STIGATION'S  OF  I  >I8E  ISES  OF  l'lM  I  1  9. 


WASHINGTON  :  GOVERNMENT  PRINTING  OFFICE  :  1903 


BUREAU  OF  PLANT  INDUSTRY. 

Pathologist  and  Physiologist,  and  Chief  of  Bureau,  Beverly  T.  Galloway. 

Pathologist  and  Physiologist,  and  Assistant  chief  of  Bureau,  Albert  1".  Woods. 

Laboratory  of  Plant  Pathology,  Erwln  1".  Smith,  Pathologist  in  Charge. 

Investigations  of  Diseases  of  Fruits,  Merton  B.  Waite,  Pathologist  in  Charge. 

Laboratory  of  Forest  Pathology,  Haven  Metcalf,  Pathologist  in  Charge. 

'I  i  in  I,   Crop  Diseases  and  Plant  Disease    Survey,  William  A.  Orton,  Pathologist  in  charge. 

Plant  Life  History  Investigations,  Walter  T.  Swingle,  Physiologist  in  Charge. 

Cotton  Breeding  Investigations,  Archibald  D.  Shamel  and  Daniel  N.  Shoemaker.  Physiolo- 
gists  in   Charge. 

Tobacco  Investigations,  Archibald  I>.  Shamel,  Wightman  W.  Garner,  and  Ernest  II. 
Mathewson.    in    Charge. 

Corn  Investigations,  Charles  P.  Hartley,  Physiologist  in  Charge. 

Alkali  and  Drought  Resistant  Plant  Breeding  Investigations,  Thomas  II.  Kearney,  Physi- 
ologist in  Charge. 

Hoil  Bacteriology  and  Water  Purification  Investigations,  Karl  P.  Kellerman,  Physiologist 
in  Charge. 

Bionomic  Investigations  of  Tropical  and  Subtropical  Plants,  Orator  I'.  Cook,  Bionomist  in 
Charge. 

Drug  and  Poisonous  Plant  Investigations  and  Tea  culture  Investigations,  Rodney  n. 
True,  Physiologist  in  charge. 

Physical  Laboratory,  Lyman  J.  Briggs,  Physicist  in  Charge. 

Crop  Technology  and  Fiber  Plant  Investigations,  Nathan  A.  Cobb,  Crop  Technologist  in 
Charge. 

Taxonomic  and  Range  Investigations,  Frederick   V.  Coville,  Botanist    in  Charge. 

Farm  Management  Investigations,  William  J.  Spillman,  Agriculturist  in  Charge. 

Cram  Investigations,  Mark  Alfred  Carleton,  Cerealist  in  Charge. 

Arlington  Experimental  Farm,  Lee  C.  Corbett,  Horticulturist  in  Charge. 

Vegetable  Testing  Gardens,  William  W.  Tracy,  sr.,   Superintendent. 

Sugar-Beet  Investigations,  Charles  O.  Townsend,  Pathologist  in  Charge. 

Western  Agricultural  Extension  Investigations,  Carl  S.  Scofield,  Agriculturist  in  charge. 

ltru  Land  Agricultural  Investigations,  V..  Channing  Chilcott,  Agriculturist  in  charge. 

Pomological  Collections,  Gustavus  B.  Brackett,  Pomologist  in  Charge. 

Field  Investigations  in  Pomology,  William  A.  Taylor  and  G.  Harold  Powell,  1'omologists 
in  Charge. 

Experimental  Gardens  and  Grounds,  Edward  M.  Byrnes,  Superintendent. 

Foreign  Seed  and  Plant  Introduction,  David  Fairchild,  Agricultural  Explorer  in  ('barge. 

Forage  Crop  Investigations,  Charles  V.  Piper,  Agrostologist  in  Charge. 

Seed  Laboratory,  Edgar  Brown,  Botanist  in  Charge. 

Grain  Standardization,  John  I  >.  Shanahan,  Expert  in  Charge. 

Subtropical  Laboratory  and   Garden,  Miami.  Fin.,  Ernst  A.  Bessey,   Pathologist  in  Charge. 

rinni  Introduction  Garden,  Chico,  Col.,  August  Mayer,  Expert  in  Charge. 

South  Texas  Garden,  Brownsville,  Tex.,  Edward  C.  Green,  Pomologist  in  Charge. 

Cotton    Cull  me   farms   and   Canines'  Cooperative     Demonstration    Work,   Seaman    A.    Knapp, 

Special  Agent   in  Charge. 
Seed  Distribution    (Directed  by   Chief  of  Bureau),   I. isle  Morrison.   Assistant    in   General 
Charge. 


Editor,  .1.  E.  Rockwell. 
Chief  Clerk,  .lames  E.  Jones. 


[Cir.  l] 
2 


'  ONTENTS. 


Introduction 

Sulphur  as  a  i  

The  Belf-boiled  lime-sulphur  mixture 

I'"  paral  ion  i  i  the  mixture  

Apple  bitter-rol  experiments 8 

Experiments  in  the  treatment  of  other  apple  diseases 11 

\  !>(•!-   blotch 

Apple  leaf-spol   .„ 

Apple  scab [2 

Experiments  in  thi   treatment  of  peach  diseases 19 

h  brown-rol  and  scab  |., 

Peach-leaf  diseases ,,. 

bined  fungicide  and  insecticide li; 

Range  of  possible  usefulness r 

[Cir.l] 

3 


ILLUSTRATIONS 


Page. 
Fig.  1.  Crop  of  apples  from  a  Ben  Davis  tree  sprayed  three  times  with  self- 
boiled  lime-sulphur  mixture JO 

2.  Crop  from  an  untreated  Hen  Davis  tree  in  the  same  i  irchard  as  that  sip  >wn 

in  figure  1 11 

[Cir.  1] 

A 


n.  r.  i 


SELF-BOILED  LIME-SULPHUR  MIXTURE  AS 
A  PROMISING  FUNGICIDE. 


INTRODUCTION. 

The  well-known  toxic  action  of  Bordeaux  mixture  <>n  peach  Foliage, 
which  renders  ii  pracl  icallj  useless  for  the  control  of  peach  diseases  in 
the  growing  season,  led  the  writer  to  investigate  other  possible  fungi- 
cides that  mighl  prove  less  caustic.  Moreover,  Bordeaux  mixture, 
although  remarkably  beneficial  in  the  control  of  fungous  diseases,  even 
stimulating  the  ^rr< > \\  1 1 1  of  plants  in  addition  to  its  fungicidal  effect,  is 
unfort  unaleh  often  injurious  to  the  fruit  and  foliage  of  the  apple  ami 
some  other  plants.  The  fruil  russeting  and  foliage  injury  caused  by 
Bordeaux  mixture  in  the  case  of  the  apple  ha-  Keen  the  subject  of 
much  complaint  in  recent  year-,  thus  increasing  the  demand  for  a 
fungicide  t  hat  can  he  used  on  grow  ing  plant-  u  it  hout  danger  of  injury. 

'The  investigations  of  fungicide's  in  which  various  sulphur  com- 
pound-, a-  well  as  other  substances,  were  tested,  have  extended  over 
several  years,  bul  no  satisfactory  results  were  obtained  until  last  sea- 
son, when  the  self-boiled  lime-sulphur  wash  was  tried  and  proved  to  be 
sufficiently  active  to  prevent  fungous  diseases  without  injuring  the 
plain-  treated.  Although  the  results  reported  in  the  following  p 
are  exceedingly  encouraging,  it  should  he  distinctly  understood  that 
this  fungicide  in  the  self-boiled  form  i-  in  ii-  experimental  stage  and 

mi:  t"  the  remarkable  progress  that  has  been  made  in  the  treatmenl  "f  plant 

diseases  by  fungicides,  anything  new  in  this  field  is  <>i'  the  utmost  importance  and 

esthe  i  no- 1  can  ■nil  attention  on  the  part  of  investi  1  fniit  growers.     This 

tls  a  new  step  in  the  use  of  sulphur  as  a  fungicide      Here  we  have  for  the 

first  time  a  fungicide  which  apparently  can  In-  safelj  used  "ii  growing  peach  foliage. 

The  susceptibility  <>i  peach  foliage  t<>  injury  by  Bordeaux  mixture  and  other  coppi  r 

utirely  in  prevenl  their  use  in  the  treatment  <>i  peach 
1  i  pple  ih'    injurious  effect   in  russeting  the  fruit  and  burning  the 

has  to  a  much  less  extent,  but  -i  ill  seriously,  inn  Tiercel  with  the  otherwise  suc- 
cessful use  of  copper.  This  situation  makes  the  development  of  a  fungicide  which  will 
obviate  these  difficulties  of  greal  imp  The  results  recorded  are  indeed  remark- 

able and  definite,  1ml  inasmuch  as  they  depend  mi  a  single  season's  experimenl 
Scott  has  vi  rly  cautioned  fruil  growers  against  their  general  application  until 

they  are  corroborated  byfurther  experiments.     B.   T    G 
Physiologist  ami  <  i 


b  Ll  ME -SULPHUR    MIXTURE   AS    A    FUNGICIDE. 

has  not  been  sufficiently  tested  to  justify  its  general  recommendation. 
For  the  present,  its  use  is  advised  for  trial  only,  and  the  object  of  this 
preliminary  paper  is  to  show  the  rather  striking  results  so  far  obtained 
and  make  them  available  to  investigators  and  fruit  growers  as  a  basis 
for  further  experiments,  in  order  that  the  value  of  the  mixture  may  lie 
more  speedily  determined.  The  Bureau  of  Plant  Industry  will  con- 
tinue the  investigations,  and  it  is  hoped  that  at  the  end  of  another 
season  definite  recommendations  can  be  made  for  the  use  of  this  wash 
or  some  modification  of  it  in  the  treatment  of  orchard  diseases. 

A  similar  self-boiled  wash  has  some  slight  reputation  as  a  dormant 
treatment  for  the  San  Jose  scale,  and  a  few  fruit  growers  have  used 
it  rather  extensively  for  this  purpose,  but  it  seems  to  have  had  very 
little  consideration  as  a  fungicide  and  has  apparently  never  been 
recommended  for  use  on  plants  in  foliage.  Curiously  enough,  how- 
ever, as  early  as  1833,  before  the  general  use  of  fungicides,  Dr.  Wil- 
liam Kenrick a  recommended  for  mildew  on  grapes  a  mixture  of 
sulphur  (14  pints),  quicklime  (a  piece  the  size  of  the  fist),  and  boiling 
water  (2  gallons).  This  mixture,  after  cooling,  was  diluted  with 
cold  water  and  allowed  to  settle.  The  clear  liquid  was  then  drawn 
off  and  diluted  to  make  a  barrel  full  before  using.  In  1885  William 
Saunders6  also  recommended  for  pear-blight  a  self-boiled  lime  and 
sulphur  wash  consisting  of  8  pounds  of  sulphur  and  one-half  bushel 
of  lime  with  boiling  water,  the  mixture  to  be  applied  as  a  whitewash 
with  brushes;  and  for  mildews  he  advised  applications  of  the  clear 
sulphur  liquid  drawn  off  from  this  wash  and  greatly  diluted.0 

SULPHUR  AS  A  FUNGICIDE. 

Sulphur  has  long  been  known  to  have  fungicidal  properties  and 
has  played  an  important  part  in  the  treatment  of  several  plant  dis- 
eases, notably  the  grape  powdery  mildew,  rose  mildew,  and  aspara- 
gus rust.  Previous  to  1S80  it  was  almost  the  only  fungicide  in  use, 
and  it  is  to-day  one  of  the  best  remedies  for  various  mildews.  In 
the  form  of  potassium  sulphid  it  has  for  years  been  the  chief  remedy 
recommended  for  gooseberry  mildew  and  to  a  less  extent  for  a  few 
other  diseases.     The  boiled  lime-sulphur  wash   used   as   a  dormant 

"The  New  American  Orchardist,  L833,  p.  328. 

6  Report,  U.  S.  Commissioner  of  Agriculture,  L885,  pp.  43  and  ii. 

cSince  this  article  was  prepared  Prof.  A.  B.  Cordley,  of  Oregon,  lias  presented  in 
ihi'  Rural  New  Yorker  of  March  7.  1908,  p.  202,  a  summary  account  of  his  experi- 
ments in  the  use  of  dilute  lime-sulphur  sprays  for  apple  scab,  which  sprays,  made 
from  the  well  boiled  wash  or  from  similar  proprietary  preparations,  have  also  been 
tested  on  other  fruit  trees  in  foliage,  such  as  the  pear,  peach,  plum,  prune  quince, 
and  cherry,  and  on  grapevines.  The  results  obtained  werethoughl  to  point  strongly 
to  the  conclusion  that  lime-sulphur  solutions  maj  become  a  satisfactory  substitute 
iui-  Bordeaux  mixture  for  summer  spraying. 
[Cir.    I  I 


LIME  SULPH  I   ';     \ll\  ll   RE     \>     \    II   NGN  [DE.  < 

spray  ranks  close  to  Bordeaux  mixture  in  the  treatment  of  the  peach 
leaf-curl  and  the  California  peach  blight  I  Coryneum  beyerincl'iiOxid.), 
a  serious  disease  of  the  peach  on  the  Pacific  coast.  <  )n  account  of  its 
caustic  effect  on  the  foliage  of  plants  tliis  boiled  wash  can  nol  be  used 
during  the  l:i< »\\  i i i^r  season  and  its  usefulness  as  a  fungicide  is  there- 
fore restricted  to  diseases  thai  can  be  reached  in  the  dormant  period; 
Ihii  the  self-boiled  mixture  used  in  the  experiments  reported  in  this 
paper  was  entireh  uninjurious  in  the  foliage  and  fruit  of  both  the 
peach  and  I  he  apple. 

THE   SELF  BOILED   LIME  SULPHUR  MIXTURE. 

At  intervals  during  the  pa>t  several  years  the  writer  has  made 
experiment-  with  sulphur  ami  various  sulphur  compounds  with  the 
object  of  finding  a  fungicide  that  could  he  used  during  the  growing 
period  on  fruit  trees,  especially  the  peach,  without  injury  t"  the 
foliage  or  fruit.  The  first  work  was  done  in  L901,  at  the  suggestion  of 
Mr.  M.  I>.  Waite.  and  consisted  of  experiments  with  various  sulphids, 
all  of  which  proved  injurious  to  peach  foliage.  During  the  season 
df  L907  self-boiled  lime-sulphur  mixtures  in  various  proportions  and 
strengths  were  tested  on  both  the  apple  and  the  peach. 

PREPARATION    OF   THE    MIXTURE. 

The  mixture  that  ura\e  the  most  promising  results  was  composed 
of  in  pounds  of  sulphur  .  flowers  or  flour)  and  \~>  pounds  of  fresh  stone 
lime  to  50  gallons  of  water,"  and  may  be  prepared  as  follow-: 

Place  the  lime  in  a  50-gallon  barrel  and  pour  a  l'  or  3  gallon  bucket 
of  boiling  water  over  it.  Immediately  add  the  sulphur  and  another 
bucket  of  hot  water.  The  heat  from  the  slaking  lime  will  boil  the 
mixture  \iolently  for  several  minutes.  Some  stirring  is  necessary 
to  prevent  burning,  and  more  water  should  he  added  if  the  mass  gets 
too  thick  to  stir,  but  the  cooking  is  more  effectual  when  the  minimum 
quantity  of  water  i-  used,  usualh  From  6  to  s  gallons  being  required. 
A  piece  of  old  carpet  or  gunnysack  thrown  over  the  top  of  the  barrel 
helps  to  keep  in  the  heat.  The  boiling  will  continue  from  twentx  to 
thirty  minutes,  depending  upon  the  quality  of  the  lime.  When  the 
boiling  ceases,  dilute  with  cold  water  to  make  oil  gallons,  stir  thor- 
oughlj  and  strain  through  a  sieve  of  aboul  20  meshes  to  the  inch  in 
order  t.>  lake  oul  coarse  particles  of  lime,  hut  all  the  sulphur  should 
be  carefulh  w  orked  i  hrough. 

•  n  a  similar  manner,  enough  for  L50  gallons  ma\  he  prepared  in  a 
barrel  by  n-im:  30  pounds  of  sulphur  and  \.~,  pounds  of  quicklime, 
with  aboul  20  gallon-  of  boiling  water.  When  the  boiling  ceases,  the 
barrel  should  he  filled  with  cold  water  and  diluted  with  Inn  gallons 
more  when  transferred  to  the  spraj  tank. 


ge  18. 
I  fir.    n 


8  LIME-SULPHUR    MIXTURE    AS    A   FUNGICIDE. 

In  some  of  the  experiments  a  wash  consisting  of  5  pounds  of  sul- 
phur and  10  pounds  of  lime  to  50  gallons  of  water  gave  excellent 
results.  This  would  indicate  that  a  much  more  dilute  mixture  than 
the  10-15-50  formula  may  prove  to  be  a  satisfactory  fungicide.  The 
wash  was  also  prepared  with  cold  water  instead  of  boiling  water,  and 
in  some  cases  a  portion  of  the  lime  was  at  first  withheld  and  later 
added,  a  small  lump  at  a  time,  in  order  to  prolong  the  boiling;  but 
the  experiments  have  not  yci  been  sufficient  to  determine  definitely 
the  correct  formula  and  the  best  method  of  preparation. 

Should  the  boiling  he  very  prolonged  the  mixture  might  become 
caustic  enough  to  burn  foliage,  although  no  such  injury  developed 
in  the  experiments.  If  it  should  be  found  in  practice  that  the  use 
of  hot  water  dissolves  too  much  sulphur,  so  that  the  foliage  is  injured, 
cold  water  may  be  substituted  and  a  less  intense  heat  thus  developed, 
or  the  sulphur  can  be  withheld  until  the  lime  has  partly  slaked, 
thus  regulating  the  amount  of  sulphur  dissolved. 

By  this  boiling  process  the  sulphur  is  put  in  good  mechanical  con- 
dition for  spraying,  and  enough  of  it  is  dissolved  to  make  the  mix- 
ture adhesive.  As  a  large  percentage  of  the  sulphur  is  simply  held 
in  mechanical  mixture  with  the  lime  water,  it  is  necessary  that  the 
spraying  outfit  be  provided  with  a  good  agitator,  so  that  the  mixture 
may  be  kept  constantly  stirred,  and  settling  be  thus  avoided.  In 
the  treatment,  of  apple  trees,  Paris  green  may  be  added  for  the  con- 
trol of  the  codling  moth  in  the  same  manner  as  when  Bordeaux  jnix- 
ture  is  used. 

APPLE  BITTER-ROT  EXPERIMENTS. 

The  work  on  apples  was  done  at  Bentonville,  Ark.,  and  the  prin- 
cipal disease  involved  was  bitter-rol  (Glomerella  rufomaculans  (Berk.) 
S.  and  v.  S.)-  This  disease  began  to  appear  in  the  orchard  of  ('apt. 
George  T.  Lincoln  on  July  8,  1907,  and  on  July  12  the  w  riter,  assisted 
by  Mr.  James  B.  Rorer,  sprayed  a  block  of  2-1  trees  with  this  lime- 
sulphur  mixture,  adding  6  ounces  of  Paris  green  to  each  50  gallons: 
a  second  block  of  21  trees  with  the  same  mixture,  substituting  2 
pounds  of  arsenate  of  lead  for  the  Paris  green,  and  a  third  block  of 
about  100  trees  with  Bordeaux  mixture  (5  pounds  of  bluestone  and 
5  pounds  of  lime  to  50  gallons  of  watei  i  and  arsenate  of  lead.  A 
block  of  24  trees  was  left  untreated  as  a  check.  About  half  of  the 
trees  in  each  block  were  Ben  Davis  and  the  other  half  (livens. 

These  1  real  incuts  were  repeated  on  July  26  and  again  on  August  27, 
1907.  When  the  first  application  was  made  (July  12)  some  bitter-rot 
was  showing  on  both  varieties,  as  manj  as  fifteen  or  twenty  affected 
fruits  being  found  on  a  number  of  individual  trees.  Although  the 
season  was  comparatively  dry,  the  showers  that  came  at  rather  long 

[Cir.    1] 


LIME-SULPHUB    -MIX  I  i   R]      \s    A    FUNGICIDE. 


9 


intervals  permitted  of  Infections  sufficient  to  destroy  a  l;u  •_:.'  portion 
of  i he  crop  on  i  he  urn  reated  i  pees. 

The  crop  of  Ben  Davis  apples  was  picked  on  September  17  and  L8, 
ami  the  Givens  on  October  in.  The  apples,  including  the  windfalls, 
from  several  average  trees  of  each  plol  were  sorted  with  reference 
to  bitter-rot  into  diseased  and  sound  fruit.  The  results  are  shown 
in  Tables  I  and  1 1. 

Table  I.     -I/'/''''  bitter-rot  ■■>•   Ben   Davis  trees       Comparative   results  from  treatment 
with  lime-sulphur  mixt  Bordeaux  mixture,  andfrcin  checks. 


Trees  spri 1  July  12  and  26  and   August  27, 19 

Number 
of  sound 
apples. 

Number 
of  dis- 
eased 

Percent- 
age of 

sound 
fruit. 

Lime-sulphur  mixture: 

1,651 

510 

1,256 

791 

572 

215 
142 

164 

40 

98 

29 
52 

lis 

1,055 
611 

90  96 

■ 

Mo.  .">                             

92.  02 

i\  mixture: 

96.  16 

Mo   8 



Trees  not  sprayed: 

eh.,  k(                

Check  D                 

• 

(  heck  i           

Although  bitter-rol  \\  as  severe  enough  on  the  Ben  Davis  trees  to 
destroy  from  80  to  90  per  ceni  of  i lie  crop  on  the  unsprayed  trees, 
the  lime-sulphur  mixture  held  it  down  to  less  than  1(1  per  cent  of 
the  crop,  as  shown  in  Table  I.  See  also  figures  1  and  2.  In  this 
experiment  the  sulphur  wash  compared  favorably  with  Bordeaux 
mixture,  the  latter  giving  only  slightly  better  results.  The  disease 
had  a  considerable  start  on  the  Ben  Davis  trees  before  the  first  ap- 
plication was  made,  and  this  accounts  for  at  least  a  part  of  the 
diseased  fruit  on  the  sprayed  trees.  Slightly  better  results  with 
both  the  sulphur  and  the  copper  treatments  could  probably  have 
been  secured  had  the  first  application  been  made  a  week  earlier. 

Table   11.     .1/'/''''  bitter-rot  on  Givens  trees.     Comparah  .from  treatment 

lime-sulphur  mixtun  and  Bordeaux  mixture,  and  from  checks. 


1  rees  sprayed  July 

2  and  -''i  and  August  27 

1907. 

Number 
of  sound 

Number 

oi  <lis- 

applcs. 

Percent- 
age of 

sound 
fruit. 

Lime-sulphur  mixture: 

No.  1  

2,034 

1  .  s.'s 

1 .  458 
1,761 

721 

l  .'.'.: 
257 

is 
23 

l 

17s 
1'. 

si! 

si:, 

99  n  p 



■is  :;> 

1  r.-.    V.   ;t 

Bordeaux  mixture: 

Mi     '          

Mo .  a                        

s'i  [2 

Tree  No  '■ 

'."1.  10 

Trees  n  •!  sprayed: 

Check  \ 



Check  i  ■ 

:>7  7'i 

50219     rii.  l     ..s 


10  LT.ME-SULPHUR    MIXTURE    AS    A    FUNGICIDE. 

Bitter-rol  was  nol  so  had  on  the  Givens  as  on  t he  Ben  Davis  trees, 
but  somewhat  more  than  half  of  the  crop  on  the  unsprayed  trees  was 
destroyed  by  it,  while  the  fruit  sprayed  with  the  lime-sulphur  mix- 
ture, as  well  as  that  sprayed  with  Bordeaux  mixture,  was  only 
slightly  affected. 

It  would  appear  from  these  tables  that  the  two  fungicides  are 
equally  effective  against  bitter-rot  and  that  when  desired  the  lime- 
sulphur  mixture  may  be  substituted  for  Bordeaux  mixture  in  the 
treatment  of  this  disease.  These  results  show  that  the  self-boiled 
lime-sulphur  mixture  is  an  excellent  fungicide  under  the  conditions 
attending    this    experiment.     The    only    question    that    remains    is 


FIG.  1. — Crop  of  apples  from  a  Ben  Davis  tree  sprayed  three  times  with  self-boiled  lime-sulphur 
mixture.  The  sound  fruit  (92  percent)  is  in  the  pile  on  the  ground  and  the  fruit  affected  with 
bitter-rot  is  in  the  baskel 

whether  it  will  maintain  this  high  standard  under  more  unfavorable 
conditions,  such  as  extremely  wet  weather. 

So  far  as  the  writer  could  observe,  absolutely  no  injury  to  the  fruit 
or  foliage  developed  from  the  use  of  this  wash,  and  it  adhered  almost, 
if  not  quite,  as  well  as  Bordeaux  mixture.  At  picking  time  the 
foliage  was  still  white  with  the  mixture  and  the  fruit  had  a  good 
coat  of  it.  Again,  however,  it  must  be  remembered  that  the  sea- 
son was  comparatively  dry,  the  rainfall  for  July  being  only  0.81  inch 
and  for  August  3. 70  inches.  Although  the  mixture  seems  to  he  quite 
adhesive,  heavy  heating  rains  might  take  il  oil'  the  fruit  and  foliage, 
so  that  a  large  pari  of  its  fungicidal  value  would  he  lost. 

[fir.    1] 


l.i  A 1 1.  Ml. I'll  IK    M  :\  I  i   1:1:    \>    \    FUNGH  [DE. 


1  1 


EXPERIMENTS  IN  THE  TREATMENT  OF  OTHER  APPLE  DISEASES. 

APPLE    BL<  'I  (  II 

Another  experiment  was  conducted  on  1  > < ■  1 1  I>a\i^  trees  in  the 
orchard  of  Mr.  Jefferson.  The  principal  disease  involved  was  apple 
blotch  (Phyllosticta  solitaria  K.  and  E.).  Both  the  lime-sulphur  and 
Bordeaux  mixtures  were  used  here,  as  in  the  Lincoln  orchard.  Owing 
to  unavoidable  ilelaj  s  the  firsl  application  was  nol  made  unl  il  June  1  I . 
1  90 7.  when  i  lif  disease  had  already  gained  ;i  good  foothold.  A  second 
application  was  made  on  July  R.  The  fruii  on  the  trees  sprayed  with 
the  lime-sulphur  wash,  a^  well  as  thai  sprayed  with  Bordeaux  mixture, 


li<,  -'  i  rop  from  an  untreated  Ben  Davis  tree  in  the  same  orchard  as  that  shown  in  Ogurel.  The 
frui l  affected  with  bitter-rol  (90.5  per  cent  I  is  in  the  pile  on  the  ground  and  the  sound  fruit  is  in 
the  b 

held  up  withoul  further  infection,  while  the  checks  continued  to  go 
down  until  practically  the  entire  crop  was  destroyed  by  this  disease. 
This  is  hardly  sufficienl  evidence  to  justify  the  conclusion  thai  the 
apple  blotch  disease  will  readily  yield  to  the  lime-sulphur  treatment, 
luii  these  results  stronghj   indicate  as  much. 

Nil  apparent  injury  whatever  resulted  from  the  use  of  the  self- 
boiled  wash  in  this  orchard.  However,  a  wash  consisting  of  3  pounds 
of  sulphur  and  5  pounds  of  lime  to  50  gallons  of  water,  boiled  15 
minutes,  when  applied  to  a  few  apple  tree-  burned  the  leaves  consid- 
eralil\  and  caused  some  defoliation,  showing  that  the  boiled  mixture 
is  unsafe  for  use  on  apple  foliage. 

[Cir.    1| 


12  LIME-SULPHUR    MIXTURE   AS    A    FUNGICIDE. 

APPLE    LEAF-SPOT. 

In  both  the  Lincoln  and  the  Jefferson  orchards  the  foliage  on  the 
trees  sprayed  with  the  lime-sulphur  wash  did  not  become  affected 
with  the  leaf-spot  disease  (Sphaeropsis  maZorum  Pk.),  except  from 
some  early  infections  that  took  place  before  the  treatment  was  made. 
The  leaves  on  these  trees  remained  fresh  and  green  until  frost.  On 
the  other  hand,  the  unsprayed  trees  left  as  checks  were  partly  defo- 
liated a  month  or  more  before  the  normal  period  of  leaf  fall.  It 
appears,  therefore,  that  the  leaf-spot  disease  may  be  readily  pre- 
vented by  the  use  of  this  lime-sulphur  wash. 

APPLE    SCAB. 

Very  little  scab  (Venturia  inaequalis  (Cke.)  Adh.)  occurred  in  either 
orchard,  and  no  definite  data  on  the  control  of  this  disease  were 
obtainable.  The  results  with  bitter-rot,  however,  were  so  excellent 
as  to  indicate  that  similar  success  with  this  wash  might  be  expected 
in  the  treatment  of  apple  scab,  and  perhaps  pear  scab  as  well.  Bor- 
deaux mixture  has  been  so  efficient  in  the  control  of  scab  that  it  would 
seem  undesirable  to  replace  it  with  another  fungicide  except  to  avoid 
the  russeting  of  the  fruit  and  the  foliage  injury  often  following  its  use. 

EXPERIMENTS  IN  THE  TREATMENT  OF  PEACH  DISEASES." 

The  work  on  the  peach  was  done  in  the  orchard  of  Ilitt  Brothers, 
at  Koshkonong,  Mo.,  in  cooperation  with  the  Missouri  Fruit  Experi- 
ment Station,  Messrs.  F.  W.  Faurot  and  T.  W.  Ayres  assisting.  A 
block  of  6-year-old  Elberta  trees  was  divided  into  30  plots  of  5  trees 
each  and  several  different  mixtures  in  addition  to  the  self-boiled 
lime-sulphur  wash  were  tried.  Bordeaux  mixture  used  in  several 
different  strengths  was  so  injurious  to  the  foliage  that  it  was  mostly 
dropped  from  the  experiment  after  the  second  treatment;  sulphuric 
acid,  1  part  to  1,000  parts  of  water,  not  only  defoliated  the  trees  but 
caused  the  entire  crop  of  fruit  to  drop;  and  a  lime-sulphur  wash  con- 
sisting of  11  pounds  of  sulphur  and  3  pounds  of  lime  to  50  gallons  of 
water,  boiled  forty-five  minutes,  burned  the  leaves  and  partly  defo- 
liated the  trees. 

PEACH    BROWN-ROT    AND    SCAR. 

The  self-boiled  lime-sulphur  mixture  heretofore  described  did  not 
injure  the  peach  foliage  or  fruit  and  proved  to  be  a  strong  fungicide 
in  its  effect  on  both  brown-rot  and  peach  scab,  as  well  as  on  some 

"  In  a  paprr  before  the  American  Pomological  Society,  read  mi  September  25,  1907, 
the  writer  gave  a  summary  of  these  experiments  ami  outlined  the  principal  results 
obtained. 

[Cir.   lj 


LIME-SULPHUB    MIXTURE    VS    \    FUNGICIDE. 


13 


leaf  diseases.     Unboiled  sulphur  with  milk  of  lime  and  pure  sulphur 
suspended  in  water  were  also  used  with  promising  results. 

The  treatments  of  the  several  plots  of  mosl  interest  and  the  results 
on  brown-rot  {Sclerotinia  fructigena  (P.)  Schrt.)  and  seal),  or  black- 
spot  (Cladosporium  carpophilum  Thiim.),  arc  condensed  in  the  fol- 
low ing  i able: 

Tumi    III        Treatments  awl  results  of  experiments  obta  gicides  on 

rot  and  scab  of  peach. 


Mixtures  used. 

of  spraying,  I'.hit. 

Total 

fruits. 

affected 

with 

brown-rot. 

lies 

Plot. 

22 
22 

22 
22 

June 

June. 

July. 

affei  ' 
with  • 

1 

2 

Lime-sulphur 

self 
Llme-sulph                 I     self- 

fi 
6 

6 

20 

■Jii 

20 
20 

10 

:. 

5 

5 
5 

5 

2 

-' 
2 

13 

13 

13 
13 

13 
13 

No. 
1,329 

1,574 
1,132 

1,356 

No. 

• 

250 
220 

212 

507 

381 

1,444 

P.  Ct. 

14 
30 

is.  7 

19.8 

37.  4 
21.2 
7:i.  3 

No.     P.ct 
5ii        4.  3 

227 

i 
- 

Sulphur  and  lime  milk 

Sulphur  water  I  in  SO) 

sulphur  -In  15  .'in  .self- 
boiled  . . . 

Liime-sulpl 
boiled 

in" 
11          X  4 

90 

24 

boiled ....                      

523 

27 

728 

40.  "> 

i 

10  urn  reated  i  rees 

28.  1 

o  in  pounds  of  sulphur  and  15  pounds  of  quicklime  to  ."iii  gallons  of  water. 

Plot  l.  as  shown  in  the  foregoing  table,  was  sprayed  five  times 
with  a  self-boiled  lime-sulphur  mixture  composed  of  H»  pounds  of 
sulphur  and  15  pounds  of  quicklime  to  50  gallons  of  water,  prepared 
in  i  he  same  manner  as  described  on  page  7.  The  trees  were  spraj  ed 
on  Ma\  22,  June  6,  June  20,  Jul}  5,  and  July  13,  1907,  the  last  dale 
being  about  two  weeks  before  the  fruit  matured.  The  crop  was 
picked  from  .Inly  30  to  August  7.  and  the  five  trees  yielded  1,329 
fruits,  10.4  per  cent  of  which  were  affected  with  brown-rot.  This 
seems  rather  encouraging  when  73.3  per  cent  of  the  crop  on  the 
check  trees  in  adjacent  rows  rotted.  Moreover,  only  !..">  per  cent 
of  the  crop  showed  nn\  marks  of  scab,  and  mosl  of  these  were  ver\ 
small, almost  unnoticeable  specks.  Mr.  Ayres,  who  was  on  the  ground 
constantly,  reports  that  the  leaves  showed  no  injury  at  any  time  dur- 
ing the  season-,  and  when  the  writer  made  a  final  examination  on 
August  27  the  foliage  was  still  green  and  apparent!}  uninjured.  The 
mixture  had  adhered  so  well  that  the  leaves  and  branches  were 
whit  ish  on  t  hat  dale. 

l'lot  2  had  the  same  treatment  as  plol  I.  except  thai  the  formula 
in  this  case  w.-i^  reduced  to  5  pounds  of  sulphur  and  10  pounds  of 
lime  to  50  gallons  of  water.  The  results  were  about  the  same  a--  in 
the  firsl  plot,  10.3  per  cenl  of  the  crop  being  affected  with  brown- 
rot  and  9.3  per  cent   with  scab.     The  foliage  was  uninjured  and  the 

[Clr.    11 


14  LIME-SULPHUR    MIXTURE   AS   A  FUNGICIDE. 

mixture  adhered  well  throughout  the  summer.  This  would  indi- 
cate that  a  weaker  mixture  than  that  used  in  plot  1  may  prove  to 
be  satisfactory,  thus  cheapening  the  treatment. 

Plot  3  was  sprayed  on  the  same  dates  as  plots  1  and  2  with  an 
unboiled  sulphur  and  lime-milk  mixture  composed  of  10  pounds  of 
sulphur  and  10  pounds  of  lime  to  50  gallons  of  water.  The  lime  was 
slaked  in  the  ordinary  way  and  the  sulphur  worked  into  it,  forming  a 
paste.  Then  the  mixture  was  diluted  to  make  50  gallons.  This 
mixture  was  more  difficult  to  apply,  required  more  agitation,  and 
did  not  adhere  so  well.  However,  it  held  the  rot  down  to  14  per  cent 
of  the  crop  and  the  scab  to  6.9  per  cent,  indicating  that  it  has  con- 
siderable fungicidal  value. 

Plot  4  was  sprayed  on  the  same  dates  as  the  three  plots  previously 
mentioned  with  10  pounds  of  sulphur  suspended  in  50  gallons  of 
water.  The  sulphur  was  worked  into  a  paste  and  then  diluted. 
The  rot  on  this  plot  was  30  per  cent  of  the  crop,  and  the  treatment 
for  this  disease  was  therefore  practically  a  failure.  However,  only 
3.4  per  cent  of  the  fruit  was  affected  with  scab.  The  sulphur  with- 
out the  lime  seems  to  have  been  entirely  sufficient  to  control  this 
disease.  Sulphur  settles  readily  in  water  and  is  rather  difficult 
to  keep  in  suspension. 

Plot  20  was  sprayed  with  the.  same  self-boiled  mixture  as  plot  1 ,  and 
the  applications  were  made  on  the  same  dates,  except  that  in  this  case 
the  first  application  (May  22)  was  omitted.  The  percentage  of  rot, 
18.7  per  cent,  was  rather  high,  owing  apparently  to  the  omission  of  the 
May  treatment.  However,  only  8.8  per  cent  of  the  crop  was  affected 
with  scab.  A  few  scab  infections  had  taken  place  before  the  treat- 
ment was  begun,  and  on  unsprayed  trees  this  disease  developed  quite 
rapidly  after  the  middle  of  June. 

Plot  23  was  sprayed  on  July  2  and  13  with  the  same  self-boiled 
mixture  used  on  plots  1  and  20,  only  two  applications  being  made. 
Of  the  crop,  19.8  percent  rotted  and  29.4  per  cent  was  affected  with 
scab.  The  fruit  was  already  badly  "scabbed"  before  the  treatment 
was  begun,  and  the  cracking  due  to  this  disease  opened  the  way 
for  brown-rot. 

Plot  24  was  sprayed  on  July  2  with  the  same  mixture  as  plots  1 ,  20, 
and  23.  Only  one  application  was  made,  and  it  was  quite  insufficient 
for  both  brown-rot  and  scab,  37.4  per  cent  of  the  crop  being  affected 
with  the  former  disease  and  38.6  per  cent  with  the  latter. 

Plot  27  was  sprayed  with  Bordeaux  mixture  consisting  of  1  pound 
of  copper  sulphate,  5  pounds  of  lime,  and  50  gallons  of  water.  The 
applications  were  made  <>n  duly  2  and  13,  with  the  result  that  21.2  per 
cent  of  tin'  crop  was  affected  with  brown-rot  and  40.5  percent  with 
seal).  The  treatment  was  entirely  too  late  for  scab,  but  had  some 
[Cir.   1J 


l.i  mi    SI  i.l'liri;    MIX  i  i   1:1     ISA  Fl   NGK  IDE.  I  5 

effect  on  brown  rot.  These  results  were  aboul  the  same  as  those  se- 
cured on  plol  23,  which  was  sprayed  on  the  same  dates  with  the  self- 
boiled  lime  sulphur  mixture.  The  plots  on  w  Inch  spraj  ing  with  Bor- 
deaux mixture  was  commenced  on  May  22,  when  the  sulphur  treat- 
ment was  begun,  were  abandoned  on  account  of  severe  foliage  injur]  . 
These  plots,  not  having  been  carried  through  the  season,  are  omitted 
from  the  table. 

On  the  check  plot,  consisting  of  10  untreated  trees  located  in  rows 
adjacent  to  the  sprayed  rows.  73.3  per  cenl  of  the  crop  was  affected 
with  hroun-rot  and  28.1   percent  with  scab. 

A  glance  al  Table  III  shows  thai  sulphur,  wherever  used  in  this 
experiment,  whether  self-boiled  <>r  unboiled,  applied  once  or  oftener, 
had  more  or  less  ell'ect  on  the  brown-rot  disease.  Where  the  self- 
boiled  wash  of  both  full  strength  and  half  strength  was  used,  nearly 
90  per  ccni  df  i lie  crop  came  through  U'cc  from  the  disease.  Owing, 
perhaps,  to  the  late  spring  frosts,  some  of  the  peach  pits  cracked  and 
there  was  considerable  proliferation  around  them,  which  resulted  in  a 
cracking  of  the  skin,  thus  exposing  the  fruit  even  on  sprayed  trees  to 
brown-rot  infection.  This,  together  with  insect  punctures,  partly 
accounts  for  the  10  per  cent  of  loss  on  plots  ]  and*2.     A  comparison 

of  these  two  plot-  indicates  that  .">  pounds  of  sulphur  in  the  mixture 
is  just  as  good  as  10  pounds,  the  larger  quantity  apparently  being 
unnecessary. 

It  must  he  understood  that  the  writer  does  not  consider  this  single 
series  of  experiments  sufficient  to  justify  final  conclusions  upon  w  Inch 
to  base  orchard  practice.  Not  until  these  results  have  been  verified 
under  different  conditions  can  the  treatment  he  recommended  with 
full  confidence. 

It  is  not  at  all  surprising  that  this  sulphur  mixture  should  be  a 
good  fungicide;  the  gratifying  surprise  is  that  it  does  not  injure  peach 
foliage.  Under  different  weather  conditions  or  when  boiled  with  a 
more  active  grade  of  lime  it  mighl  prove  injurious,  and  for  this  reason 
caution  should  he  exercised  until  further  knowledge  of  its  action  is 
obtained. 

Although  occasional  rains  occurred  at  Koshkonomr.  Mo.,  while  the 
experiment  was  in  progress,  the  season  would  he  considered  rather 
dry.  The  rainfall  there  as  recorded  by  the  voluntary  observer,  Mr. 
John  W.  Ilitl.  was  as  follows:  For  the  month  of  May.  L0.89  inches; 
June,  L9  inches;  and  July,  t .67  inches.  Enough  rain  fell  to  produce 
considerable  injury  to  peach  foliage  following  applications  of  Bor- 
deaux mixtun  a  in  I  to  cause  a  severe  outbreak  of  brown-rot.  During 
a\cr\  wet  season,  however,  the  treatment  mighl  not  be  so  successful; 

in  fact,  this  disease  is  influenced  by  so  n\   factors  that    it  seems 

doubtful  whether  an  entirely  satisfactory  treatment  for  it  will  ever  be 

[Cir.    1] 


16  LIME-SULPHUR    MIXTURE   AS   A  FUNGICIDE. 

found.  The  plum  curculio  punctures  the  skin  of  a  certain  percentage 
of  the  fruit  and  thus  admits  the  fungus  in  spite  of  all  spraying  that  can 
be  done;  also,  some  of  the  leaf-footed  plant  bugs  feed  on  the  rotting 
and  the  sound  fruit  indiscriminately,  thus  undoubtedly  distributing 
the  fungus  and  perhaps  even  with  their  beaks  inserting  the  spores  be- 
neath the  skin  of  the  fruit.  It  seems  quite  impossible  to  protect 
against  such  infections: 

In  the  case  of  peach  scab  the  results  were  very  decided.  In  every 
plot  where  sulphur  was  used  before  infection  took  place,  this  dis- 
ease was  almost  completely  controlled.  Even  sulphur  suspended  in 
water  without  the  addition  of  lime  seems  to  be  sufficient  to  control 
this  disease.  As  a  rule,  the  seal)  infections  on  the  sprayed  fruit  were 
manifested  in  small  specks  instead  of  the  large  spots  and  cracks  that 
were  so  common  on  the  unsprayed  fruit. 

PEACH-LEAF    DISEASES. 

The  frosty  mildew  (Cercosporella  persicae  Sacc.)  was  also  con- 
trolled by  the  self-boiled  lime-sulphur  mixture  (10-15-50).  This  was 
demonstrated  especially  on  Picquet's  Late,  which  variety  was  sprayed 
on  July  26  and  again  on  August  8.  The  writer  examined  the  trees  on 
August  27  and  found  the  foliage  in  a  vigorous,  healthy  condition, 
practically  free  from  leaf  diseases,  while  the  leaves  of  the  unsprayed 
trees  were  badly  affected  with  the  frosty  mildew,  had  turned  yellow, 
and  were  falling  considerably.  Some  of  these  leaves  were  also  af- 
fected with  a  shot-hole  disease  due  apparently  to  Bacterium  pruni 
Smith,  but  none  of  this  could  be  found  on  the  sprayed  trees. 

A  COMBINED  FUNGICIDE   AND  INSECTICIDE. 

Self-boiled  lime-sulphur  washes  used  in  the  dormant  spraying  of 
fruit  trees  are  known  to  have  some  effect  against  the  San  -lose  scale, 
and  in  order  to  avoid  the  expense  of  a  cooking  plant  a  few  growers 
have  employed  this  method  of  preparing  the  wash.  Entomologists 
have  wisely  discouraged  the  use  of  self-boiled  washes  because  of  their 
inferiority  to  the  boiled  preparations,  but  when  used  as  a  fungicide 
in  the  growing  season  a  self-boiled  lime-sulphur  wash  might  be  ex- 
pected to  aid  considerably  in  the  control  of  the  San  dose  scale  and 
other  scale  insects  by  the  destruction  of  the  crawling  lice,  and  would 
thus  perhaps  prevent  the  infestation  of  the  fruit,  a  condition  espe- 
cially likely  to  occur  witli  apples  and  pears.  This  would  give  it  a 
decided  advantage  over  Bordeaux  mixture  and  make  it  especially 
useful  as  a  combined  fungicide  and  insecticide  in  the  treatment  of 
large  apple  trees  on  which  (he  scale  is  so  difficult  to  control.  Summer 
applications  for  the  prevention  of  fungous  diseases  would  thus  sup- 
[Cir.    11 


l.i. Ml    SULPHUB     MIXTURE    \s    \    FUNGICIDE.  17 

plement  the  dormanl  treatmenl  of  the  San  Jose  scale  withoul  extra 
cost. 

Sulphur  is  also  a  well-known  remedj  for  various  mites,  and  the 
self-boiled  wash  would  probably  be  "I'  considerable  value  in  the 
conl rol  of  the  red  spider. 

RANGE   OF  POSSIBLE   USEFULNESS. 

Tlic  fungicide  described  in  these  pages  i-  only  in  the  experimental 
stage,  and  it  is  impossible  to  predicl  the  extenl  of  iis  usefulness;  but 
if  it  will  control  apple  bitter-rot,  a-  the  results  so  far  obtained  indi- 
cate, ii  would  naturally  be  expected  to  prevent  apple  scab.  Al- 
though no  positive  results  were  obtained  with  this  disease,  the 
indications  were  that  it  might  easily  be  controlled  with  the  bme- 
sulphur  wash  and  the  fruit  russeting  and  foliage  injury  duo  to  the 
use  "\'  Bordeaux  mixture  thus  avoided.  Except  the  injury  follow- 
ing it-  use  in  a  wet  season,  Bordeaux  mixture  furnishes  an  entirely 
satisfactory  fungicide  for  both  apple  -call  and  bitter-rot,  perhaps 
better  than  can  he  expected  of  th  •  lime-sulphur  wash;  but  the  latter 
ha-  the  advantage  of  being  a  combined  insecticide  and  fungicide 
and  does  not  injure  the  fruit  or  foliage,  or  at  least  ii  would  so  appear 
from   these   preliminary    experiments. 

This  self-boiled  mixture  could  reasonably  l>e  expected  to  readily 
control  the  powderj  mildews  of  fruit,  some  of  which  have  long  been 
known  to  be  preventable  by  the  application  of  sulphur  in  some  form. 
Owing  to  its  greater  adhesiveness,  it  should  perhaps  largely  supplant 
drj  sulphur  and  liver  of  sulphur  in  the  treatment  of  various  mildews. 

If  the  results  of  last  year's  experiments  are  borne  out  by  further 
tests,  the  most  important  function  of  tin-  fungicide  will  doubtless 
be  the  control  of  peach  diseases.  Heretofore,  practically  no  known 
fungicide  could  he  used  on  peach  foliage  without  injurious  results, 
and  for  tin-  reason  orchardists  have  been  unable  to  combat  some  of 
the  more  important  peach  diseases  ami  to  prevent  the  annual  loss 
of  several  millions  of  dollar-'  worth  of  fruit  caused  by  them.  Bor- 
deaux mixture,  the  standard  fungicide,  can  not  be  used  <>n  peach 
tree-  during  the  growing  season  without  danger  of  serious  injury 
to  the  foliage.  While  a  weak  Bordeaux  mixture  may  he  used  in  a 
drj    season  without   injurious  results,   the  same  mixture  applied  in 

a  wet   season,  when   mosl    n led.  will   usually  defoliate  the  trees. 

The  other  forms  of  copper,  such  a-  a m nioniacal  copper  carbonate 
and   acetate  of  copper,  are  even  more  toxic  than   Bordeaux   mixture. 

It  is  apparent,  then,  that  an  efficient  cheap  fungicide  thai  can  be 
used  on  the  fruit  and  foliage  of  the  peach  withoul  injurious  results 
will  be  of  inestimable  value.  The  self-boiled  lime-sulphur  mixture 
give)    promise  of  ting  these  requirements,  and  it  is  hoped  that 

[CIr.    1] 


18  LIME-SULPHUR    MIXTURE    AS     A    FUNGICIDE. 

the  results  already  secured  will  be  substantiated  by  further  investi- 
gations. Under  some  unfavorable  weather  conditions  injury  to  the 
foliage  or  fruit  might  possibly  develop,  and  heavy  beating  rains 
might  wash  the  sulphur  away,  so  that  its  fungicidal  effect  would 
be  partly  lost.  It  seems  likely,  however,  that  a  lime-sulphur  mix- 
ture, either  self-boiled  or  unboiled,  will  prove  to  be  a  safe  and  val- 
uable fungicide  for  use  on  fruit  trees  and  other  plants  during  the 
growing  season. 

Approved: 

James  Wilson, 

Secre  tary  of  Agricultv.  re . 

Washington,  D.  C,  March  14,  1908. 


Note  to  the  Second  Edition. — Since  .the  first  edition  of  this 
circular  was  issued,  additional  results  of  the  season's  work  of  1908 
have  become  available,  particularly  the  results  of  experiments  in 
spraying  the  peach  at  Marshall ville,  Ga.  It  has  been  found  that  too 
much  sulphur  was  brought  into  solution  when  hot  water  was  used  in 
slaking  the  lime,  especially  when  material  sufficient  for  200  or  300 
gallons  was  made  up  at  one  time.  Under  the  warm,  rainy,  humid 
conditions  that  occurred  at  one  period  in  Georgia  some  injury  resulted 
to  the  peach  foliage,  there  being  enough  soluble  sulphids  in  the  solu- 
tion to  burn  the  leaves.  When  cold  water  was  used  in  slaking  the 
lime,  only  a  small  quantity  of  sulphur  is  actually  brought  into  solu- 
tion and  no  harm,  or  a  very  insignificant  amount,  occurred.  For 
use  Oil  the  peach  and  Japanese  plum,  therefore,  cold  water  instead 
of  hot  water  is  advisable  for  slaking  the  lime. 

Furthermore,  it  was  found  that  5  pounds  of  sulphur  to  ."1  pounds 
of  lime  is  entirely  sufficient  for  spraying  peach  trees,  so  that  this  for- 
mula is  now  recommended.  Where  the  precaution  of  mixing  with 
cold  water  was  taken  no  injury  to  peach  foliage  resulted.  On  the 
apple  the  stronger  mixture  made  with  hot  water  can  be  used.  It  is 
doubtful,  however,  whether  more  than  8  or  10  pounds  of  sulphur  and 
the  same  quantity  of  lime  need  be  appljed  on  the  apple  for  the  best 
results. 

[Cir.  1.] 

o 


UNIVERSITY  OF  FLORIDA 


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